Fluorinated copolymer compositions and associated methods, uses and articles

The present invention generally relates to copolymer compositions comprising the reaction product of a reaction of: (I) a cured polyorganosiloxane intermediate having repeating Si—O—Si units and at least one Si—OH functional group; and a (II) polyfluoropolyether silane.

Cured polyorganosiloxanes having repeating Si—O—Si units (“Siloxy Units”), such as those formed from polyorganosiloxane compositions curable by a hydrosilylation reaction, are used as protective or coating agents in the manufacture of various optical devices and non-optical devices. In addition, such cured polyorganosiloxanes have been used in various other applications, including, for example, for use in caulks or sealants for building or construction applications.

While these cured polyorganosiloxanes have proven suitable for their intended use in these devices and applications, dust accumulation of the surface of these cured polyorganosiloxanes may have real or perceived negative impacts on the performance of the cured polyorganosiloxanes in such devices or applications. For example, in certain optical devices, wherein the cured polyorganosiloxanes are used as protective or coating layers for the optical device that do not either absorb or dissipate light passing there through, the accumulation of dust on one or more surfaces of these cured polyorganosiloxane may adversely impact these same optical properties.

The present invention thus seeks to minimize or otherwise limit dust pickup on surfaces of cured polyorganosiloxanes (i.e., in an anti-dust surface application), particularly those cured polyorganosiloxanes used in or comprising a suitable optical device or non-optical devices or suitable application, without otherwise affecting or adversely impacting the optical properties or other physical properties of the cured polyorganosiloxanes as they relate to their intended use.

Summary of the invention

The present invention provides a copolymer composition comprising the reaction product of a reaction of: (I) a cured polyorganosiloxane intermediate having repeating Si—O—Si units and at least one Si—OH functional group; and a (II) polyfluoropolyether silane.

In certain embodiments, the cured polyorganosiloxane intermediate (I) is formed from a cured polyorganosiloxane having repeating Si—O—Si units. In these embodiments, at least one Si—OH functional group is formed on the cured polyorganosiloxane to make the cured polyorganosiloxane intermediate prior to reacting the cured polyorganosiloxane intermediate with the polyfluoropolyether silane (II).

In one embodiment, the cured polyorganosiloxane is formed by curing a curable composition comprising: (A) a polydiorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule, optionally (B) a silicone resin having an average of at least two aliphatically unsaturated organic groups per molecule and a vinyl content of up to 3%, (C) a crosslinker having an average, per molecule, of at least two silicon-bonded hydrogen atoms, and (D) a hydrosilylation catalyst. In these non-limiting embodiments, components (A), optional (B), and (C) and their amounts in the curable composition are selected such that the ratio of a total amount of silicon bonded hydrogen atoms in the curable composition/total amount of aliphatically unsaturated groups in the curable composition ranges from 0.8 to 3.0. In certain of these embodiments, (B) is present as described above.

In other embodiments, the cured polyorganosiloxane is formed by curing a curable composition comprising: (A′) an organopolysiloxane of the average structural formula R.sup.10.sub.kSiO.sub.(4-k)/2, (B′) an organopolysiloxane that contains in one molecule at least two silicon-bonded hydrogen atoms and at least 15 mole % of all silicon-bonded organic groups in the form of aryl groups; optionally (C′) a branched-chain organopolysiloxane and (D′) a hydrosilylation catalyst. In these embodiments, “k” is a number ranging from 0.6 to 2.1 and R.sup.10 designates unsubstituted or halogen-substituted monovalent hydrocarbon groups. In certain of these embodiments, (C′) is present.

In certain embodiments, the polyfluoropolyether silane is to the general formula (A″): Y—Z.sub.a—[(OC.sub.3F.sub.6).sub.b—(OCF(CF.sub.3)CF.sub.2).sub.c—(OCF.sub.2CF(CF.sub.3)).sub.d—(OC.sub.2F.sub.4).sub.e—(CF(CF.sub.3)).sub.f—(OCF.sub.2).sub.g]—(CH.sub.2).sub.h—X′—(C.sub.nH.sub.2n)—((SiR.sup.1.sub.2—O).sub.m—SiR.sup.1.sub.2).sub.i—(C.sub.jH.sub.2j)—Si—(X″).sub.3-z(R.sup.2).sub.z. In general formula (A″), Z is independently selected from —(CF.sub.2)—, —(CF(CF.sub.3)CF.sub.2O)—, —(CF.sub.2CF(CF.sub.3)O)—, —(CF(CF.sub.3)O)—, —(CF(CF.sub.3)CF.sub.2)—, —(CF.sub.2CF(CF.sub.3))—, and —(CF(CF.sub.3))—. In addition, a is an integer from 1 to 200; b, c, d, e, f, and g are integers each independently selected from 0 to 200; h, n and j are integers each independently selected from 0 to 20; and i and m are integers each independently selected from 0 to 5. Still further, X′ is a bivalent organic group or O; R.sup.1 is an independently selected C.sub.1-C.sub.22 hydrocarbyl group; z is an integer independently selected from 0 to 2; X″ is an independently selected hydrolysable group; and R.sup.2 is an independently selected C.sub.1-C.sub.22 hydrocarbyl group which is free of aliphatic unsaturation. Yet still further, Y is selected from H, F, and (R.sup.2).sub.z(X″).sub.3-zSi—(C.sub.jH.sub.2j)—((SiR.sup.1.sub.2—O).sub.m—SiR.sup.1.sub.2).sub.i—(C.sub.nH.sub.2n)—X′—(CH.sub.2).sub.h—, wherein X″, X′, z, R.sup.1, R.sup.2, j, m, i, n and h are as defined above; provided that when subscript i is 0, subscript j is also 0; when subscript i is an integer selected from 1 to 5, subscript j is an integer selected from 1 to 20 and m is an integer selected from 1 to 5.

The copolymer composition may also be used in, or comprise, optical and non-optical devices. In certain of these embodiments, the copolymer composition provides the device with improved resistance to dust accumulation as compared with the use of the cured polyorganosiloxane (I) in these devices alone.

The copolymer compositions may be used in building, OEM, electronic assembly or construction applications, such as for use in caulks, gaskets, encapsulants, gels, adhesives, conformal coatings or sealants. The copolymer composition may also protect these applications from dust accumulation.

Brief description of the drawings

FIG. 1 is a graph plotting average light transmission and standard deviation of the samples of Example 2 after dust treatment.

FIG. 2 is a graph plotting a light transmission spectrum of Sample A of Example 2 within the visible light spectrum.

Detailed description of the invention

All amounts, ratios, and percentages are by weight unless otherwise indicated. The following is a list of definitions as used in this application. Definitions

The articles “a”, “an” and “the” each refer to one or more.

The abbreviation “M” means a siloxane unit of formula R.sub.3SiO.sub.1/2, where each R independently represents a monovalent atom or group.

The abbreviation “D” means a siloxane unit of formula R.sub.2SiO.sub.2/2, where each R independently represents a monovalent atom or group.

The abbreviation “T” means a siloxane unit of formula RSiO.sub.3/2, where R represents a monovalent atom or group.

The abbreviation “Q” means a siloxane unit of formula SiO.sub.4/2.

The abbreviation “Me” represents a methyl group.

The abbreviation “Ph” represents a phenyl group.

The abbreviation “Vi” represents a vinyl group.

“Combination” means two or more items put together by any method.

The term “optical device” or “optical device application”, as defined herein, refers to any device capable of producing, conducting or controlling light. For example, such optical devices may be devices that produce and/or control light such as an optical waveguides, optical lenses, mixing chambers, lighting reflectors, light engines, troffers, optical cameras, photo-couplers, charged couplers, lightguides, light sensing elements, and LED packages such as high brightness LED (HBLED) housings. The optical device could also refer to other devices that merely control light passing there through, such as glass windows for a building.

The term “non-optical device” or “non-optical device application”, as defined herein, refers to any device that is not an optical device as defined above. For example, the non-optical device may be a device such as a keypad for a typewriter or a computer, a coaster, or the like.

As used herein, the terms “contact angle” and “CA” refer to the angle tangent at the point where a liquid drop contacts a medium (a substrate or layer coated onto a substrate). The term “water contact angle” and “WCA” refer to the angle tangent at the point where a water drop contacts a substrate or layer coated onto the substrate. The WCA therefore relates to how the water applied to the medium interacts with the surface of the medium (here the water contact angle of a surface of the cured polyorganosiloxane or the cured polyorganosiloxane intermediate) and is not a property of medium itself. Thus, when a surface of the medium is described as having a water contact angle of X°, it is referring the angle tangent at the point where a liquid drop contacts the surface of the medium. The measurement of static water contact angles pursuant to ASTM 5946-04 as described herein were measured using a VCA Optima XE goniometer produced by AST Products, Inc., Billerica, Mass. Reported data was the average WCA of six measurements at multiple places on the surface using multiple samples.

A “lightguide” means a shaped article that carries light from a point-like light source, such as an LED, to a target such as a target line or target plane by internal reflection.

“Unsubstituted hydrocarbon group” means a group made up of hydrogen and carbon atoms.

“Substituted hydrocarbon group” means a group made up of hydrogen and carbon atoms, except that at least one hydrogen atom has been replaced with a different substituent atom or group such as a halogen atom, halogenated organic group, or a cyano group.

The present invention relates generally to copolymer compositions and associated methods for forming copolymer compositions. The present invention also relates to the use of such copolymer compositions as or as a portion of optical or non-optical devices, including optical or non-optical devices as described above. In certain of these embodiments, the copolymer compositions provided the optical device or non-optical device with improved resistance to dust accumulation.

The present invention also generally relates to the use of such copolymer compositions in building, OEM, electronic assembly or construction applications, such as for use in caulks, gaskets, encapsulants, gels, adhesives, conformal coatings or sealants.

The copolymer composition of the present invention includes, as its reaction components, a cured polyorganosiloxane intermediate having repeating Si—O—Si units and at least one Si—OH functional group and a polyfluoropolyether silane, as is described further below. Copolymer Composition

In certain aspects, the present invention relates generally to copolymer composition comprising the reaction product of a reaction of (I) a cured polyorganosiloxane intermediate having repeating Si—O—Si units at least one Si—OH functional group; and (II) a polyfluoropolyether silane.

A. Component (I)—Cured polyorganosiloxane Intermediate

Component (I) of the copolymer composition is a cured polyorganosiloxane intermediate having repeating Si—O—Si units and at least one Si—OH functional group (i.e., silanol group). In certain embodiments, the surface of the cured polyorganosiloxane intermediate has a water contact angle of less than or equal to 90°, such as from 40° to 90°, as measured in accordance with ASTM 5946-04.

In certain of these embodiments, Component (I) includes M, D and T units. In certain other embodiments, Component (I) may include, M, D, T and Q units.

In certain embodiments, Component (I) may be formed from a cured polyorganosiloxane having repeating Si—O—Si units. In these embodiments, at least one Si—OH functional group is formed on the cured polyorganosiloxane to make the cured polyorganosiloxane intermediate (I) prior to reacting with the polyfluoropolyether silane (II). Methods for forming the at least one Si—OH functional group on the cured polyorganosiloxane are described in further detail below.

The cured polyorganosiloxane having Si—O—Si units, in accordance with the present invention, has a surface having a water contact angle of greater than 90°, such as from greater than 90° to 180°, such as from 100° to 135°, such as from 110° to 130°, as measured by ASTM 5946-04.

Two non-limiting examples of suitable cured polyorganosiloxanes (Non-limiting Embodiment 1” and “Non-limiting Embodiment 2”) having Si—O—Si units and having water contact angles as described in the previous paragraph used to form Component (I), and the methods for forming each of these respective cured polyorganosiloxanes, are described as follows.

Non-Limitinq Embodiment 1 of Cured Polyorganosiloxane

In one non-limiting embodiment (Non-limiting Embodiment 1), the cured polyorganosiloxane is formed by curing a curable composition comprising (A) a polydiorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule, optionally (B) a silicone resin having an average of at least two aliphatically unsaturated organic groups per molecule and a vinyl content of up to 3%, (C) a crosslinker having an average, per molecule, of at least two silicon-bonded hydrogen atoms, and (D) a hydrosilylation catalyst. In these non-limiting embodiments, component (A), optional component (B), and component (C) and their amounts in the curable composition are selected such that the ratio of a total amount of silicon bonded hydrogen atoms in the curable composition/total amount of aliphatically unsaturated groups in the curable composition ranges from 0.8 to 3.0, such as from 1.2 to 1.7.

As noted above, Component (A) comprises a polydiorganosiloxane having an average at least two aliphatically unsaturated organic groups per molecule.

An aliphatically unsaturated organic group, as defined herein, includes any carbon-containing functional group that includes, on average, at least one carbon-carbon double bond or carbon-carbon triple bond. In certain embodiments, for example, the aliphatically unsaturated organic groups are aliphatically unsaturated hydrocarbon groups.

The aliphatically unsaturated organic groups in component (A) may be alkenyl exemplified by, but not limited to, vinyl, allyl, butenyl, pentenyl, and hexenyl; alternatively vinyl. The aliphatically unsaturated organic groups may be alkynyl groups exemplified by, but not limited to, ethynyl, propynyl, and butynyl. The aliphatically unsaturated organic groups in component (A) may be located at terminal, pendant, or both terminal and pendant positions. Alternatively, the aliphatically unsaturated organic groups in component (A) may be located at terminal positions of the at least one organopolysiloxane.

The remaining silicon-bonded organic groups that may also be present in the organopolysiloxanes of component (A) may be substituted and unsubstituted hydrocarbon groups free of aliphatic unsaturation. Monovalent unsubstituted hydrocarbon groups are exemplified by, but not limited, to alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl groups such as cyclohexyl. Monovalent substituted hydrocarbon groups are exemplified by, but not limited to halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl, fluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl.

In certain embodiments, component (A) comprises a polymer combination comprising (A1) a first polydiorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule and having a viscosity of up to 12,000 mPa.Math.s (measured at 25 degrees Celsius), and (A2) a second polydiorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule and having a viscosity of at least 45,000 mPas (measured at 25 degrees Celsius).

Component (A1) can be an polydiorganosiloxane or a combination comprising two or more polydiorganosiloxanes having an average of at least two aliphatically unsaturated organic group per molecule that differ in at least one of the following properties: structure, average molecular weight, siloxane units, and sequence. As noted above, the viscosity of component (A1) is up to 12,000 mPa.Math.s (measured at 25 degrees Celsius). Alternatively, the viscosity of component (A1) may range from 300 mPa.Math.s to 12,000 mPa.Math.s, alternatively from 300 mPa.Math.s to 2,500 mPa.Math.s, and alternatively from 300 mPa.Math.s to 2,000 mPa.Math.s (measured at 25 degrees Celsius). The amount of component (A1) in the composition may range from 10% to 90%, alternatively 70% to 80%, based on the combined weight of components (A1) and (A2).

In certain embodiments, component (A1) has the general formula (I): R.sup.3.sub.3SiO—(R.sup.4SiO).sub.aa—SiR.sup.3.sub.3, wherein each R.sup.3 and R.sup.4 are independently an aliphatically unsaturated organic group or a monovalent substituted or unsubstituted hydrocarbon group as described above and the subscript a is an integer having a value sufficient to provide component (A1) with a viscosity up to 12,000 mPa.Math.s as measured at 25 degrees Celsius, with the proviso that on average at least two of the R.sup.3 and/or R.sup.4 are unsaturated organic groups. Alternatively, formula (I) may be an α,ω-dialkenyl-functional organopolysiloxane.

Component (A2) can be an polydiorganosiloxane or a combination comprising two or more polydiorganosiloxanes having an average of at least two aliphatically unsaturated organic groups per molecule that differ in at least one of the following properties: structure, average molecular weight, siloxane units, and sequence. As noted above, the viscosity of component (A2) is at least 45,000 mPa.Math.s (measured at 25 degrees Celsius). Alternatively, the viscosity of component (A2) may range from 45,000 mPa.Math.s to 65,000 mPa.Math.s (measured at 25 degrees Celsius). The amount of component (A2) in the composition may range from 10% to 90%, alternatively 20% to 30%, based on the combined weight of components (A1) and (A2).

In certain embodiments, component (A2) has the general formula (II): R.sup.5.sub.3SiO—(R.sup.6SiO).sub.bb—SiR.sup.5.sub.3, wherein each R.sup.5 and R.sup.6 are independently selected from the group consisting of aliphatically unsaturated organic groups such as the substituted or unsubstituted hydrocarbon group as described above and the subscript b is an integer having a value sufficient to provide component (A2) with a viscosity of at least 45,000 mPa.Math.s, alternatively from 45,000 mPa.Math.s to 65,000 mPa.Math.s as measured at 25 degrees Celsius, with the proviso that on average at least two of the R.sup.3 and/or R.sup.4 are unsaturated organic groups. Alternatively, formula (II) may be an α,ω-dialkenyl-functional organopolysiloxane.

The silicone resin (B) useful herein, when present, contains an average of at least two aliphatically unsaturated organic groups per molecule. The amount of aliphatically unsaturated organic groups in the resin may be up to 3.0% based on the weight of the silicone resin (B). Alternatively, the amount of aliphatically unsaturated organic groups in the silicone resin (B) may range from 1.9% to 3.0%, alternatively 2.0% to 3.0%, alternatively 1.9% to 3.0%, and alternatively 1.5% to 2.0% on the same basis.

The silicone resin (B) comprises monofunctional units (M) represented by R.sup.7.sub.3SiO.sub.1/2 and tetrafunctional (Q) units represented by SiO.sub.4/2. R.sup.7 represents a monovalent organic group, which is a monovalent substituted or unsubstituted hydrocarbon group. The silicone resin (B) is soluble in liquid hydrocarbons such as benzene, toluene, xylene, heptanes and the like or in liquid organosilicon compounds such as low viscosity cyclic or linear polydiorganosiloxanes. Exemplary solvents are listed below.

In the R.sup.7.sub.3SiO.sub.1/2 unit, R.sup.7 may be a monovalent unsubstituted hydrocarbon groups, exemplified by alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, octyl, undecyl, and octadecyl; alkenyl groups, such as vinyl, allyl, butenyl, pentenyl and hexenyl; cycloaliphatic radicals, such as cyclohexyl and cyclohexenylethyl; alkynyl groups such as ethynyl, propynyl, and butynyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and aromatic groups such as ethylbenzyl, naphthyl, phenyl, tolyl, xylyl, benzyl, styryl, 1-phenylethyl, and 2-phenylethyl, alternatively phenyl. Non-reactive substituents that can be present on R.sup.5 include but are not limited to halogen and cyano. Monovalent organic groups which are substituted hydrocarbons groups are exemplified by, but not limited to, halogenated alkyl groups such as chloromethyl, 3-chloropropyl, 3,3,3 trifluoropropyl, fluoromethyl, 2-fluoropropyl, 4,4,4 trifluorobutyl, 4,4,4,3,3-pentafluorbutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl.

The silicone resin (B), when present, may have a ratio of M units to Q units (M:Q ratio) ranging from 0.6:1 to 1.1:1. The silicone resin (B) comprising R.sup.7.sub.3SiO.sub.1/2 units and SiO.sub.4/2 units may have a number average molecular weight ranging from 2,000 to 5,000, see Lee, et al., U.S. Pat. No. 6,124,407 for a description of suitable silicone resins and how to prepare them. The number-average molecular weight (M.sub.n) may be determined by gel permeation chromatography employing a low angle laser light scattering detector, or a refractive index detector and silicone resin (MQ) standards.

The silicone resin (B) can be prepared by any suitable method. Silicone resins of this type have reportedly been prepared by cohydrolysis of the corresponding silanes or by silica hydrosol capping methods known in the art. The silicone resin may be prepared by the silica hydrosol capping process of Daudt, et al., U.S. Pat. No. 2,676,182; of Rivers-Farell, et al., U.S. Pat. No. 4,611,042; of Butler, U.S. Pat. No. 4,774,310; and Lee, et al., U.S. Pat. No. 6,124,407.

The intermediates used to prepare the silicone resin (B) are typically triorganosilanes of the formula R.sup.7.sub.3SiJ′, where R.sup.7 is as described above and J′ represents a hydrolysable group, and either a silane with four hydrolysable groups, such as halogen, alkoxy or hydroxyl, or an alkali metal such as sodium silicate.

It is desirable that the content of silicon-bonded hydroxyl groups (i.e., HOSiO.sub.3/2 groups) in the silicone resin, when the silicone resin is present, be below 0.7% of the total weight of the silicone resin, alternatively below 0.3%. Silicon-bonded hydroxyl groups formed during preparation of the silicone resin may be converted to trihydrocarbylsiloxy groups or hydrolyzable groups by reacting the silicone resin with silane, disiloxane or disilazane containing the appropriate terminal group. Silanes containing hydrolyzable groups are typically added in excess of the quantity required to react with the silicon-bonded hydroxyl groups of the silicone resin.

The silicone resin (B), when present, may be one silicone resin. Alternatively, the silicone resin (B), when present, may comprise two or more silicone resins, where the resins differ in at least one of the following properties: structure, hydroxyl and/or hydrolyzable group content, molecular weight, siloxane units, and sequence. The amount of silicone resin in the composition may vary depending on the type and amounts of polymers present, and the aliphatically unsaturated organic groups (e.g., vinyl) content of components (A) and (B), however, when present the amount of silicone resin (B) may range from 25% to 40%, alternatively 26% to 38%, by weight of the cured diorganosiloxane composition.

Component (C) is a crosslinker having an average, per molecule, of at least two silicon-bonded hydrogen atoms. Component (C) may comprise a polyorganohydrogensiloxane or a resinous organohydrogen silica structure. Component (C) can be a single polyorganohydrogensiloxane or resinous organohydrogen silica structure or a combination comprising two or more polyorganohydrogensiloxanes or resinous organohydrogen silica structures that differ in at least one of the following properties: structure, viscosity, average molecular weight, siloxane units, and sequence.

In certain embodiments, component (C) is a linear polyorganohydrogensiloxane of general formula (IV): HR.sup.8.sub.2SiO—(R.sup.8SiO).sub.cc—SiR.sup.8.sub.2H, where each R.sup.8 is independently a hydrogen atom, or a monovalent organic group or a monovalent hydrocarbon group, which is a monovalent substituted or unsubstituted hydrocarbon group, with the proviso that on average at least two R.sup.8 per molecule are hydrogen atoms as exemplified above by R.sup.5, with the proviso that at least two R.sup.8 per molecule are hydrogen atoms, and subscript cc is an integer with a value of 1 or more. Alternatively, at least three R.sup.8 per molecule are hydrogen atoms and cc may range from 1 to 20, alternatively 1 to 10. Component (C) may comprise a hydrogen terminated organopolysiloxane. Alternatively, component (C) may comprise a poly(dimethyl/methylhydrogen)siloxane copolymer with or without terminal silicon-bonded hydrogens.

Alternatively, in certain embodiments, component (C) is a branched polyorganohydrogensiloxane of the unit formula (IV): (R.sup.9SiO.sub.3/2).sub.dd(R.sup.9.sub.2SiO.sub.2/2).sub.ee(R.sup.9SiO.sub.1/2).sub.ff(SiO.sub.4/2).sub.gg(X′″O).sub.hh, wherein X′″ is an alkoxy-functional group. Each R.sup.9 is independently a hydrogen atom or a monovalent organic group or a monovalent hydrocarbon group, which is a monovalent substituted or unsubstituted hydrocarbon group as exemplified above for R.sup.7, with the proviso that an average of at least two per molecule of R.sup.9 are hydrogen atoms. In formula (IV), the branched polyorganohydrogensiloxane contains an average of at least two silicon bonded hydrogens per molecule, however 0.1 mol % to 40 mol % of R.sup.9 may be hydrogen atoms.

In formula (IV), the subscript dd is a positive number, subscript ee is 0 or a positive number, subscript ff is 0 or a positive number, subscript gg is 0 or a positive number, subscript hh is 0 or a positive number, e/d has a value ranging from 0 to 10, ff/ee has a value ranging from 0 to 5, gg/(dd+ee+gg+ff) has a value ranging from 0 to 0.3, and hh/(dd+ee+gg+ff) has a value ranging from 0 to 0.4.

The amount of component (C) added is sufficient to provide that SiH/Vi ratio is in a range from 0.8 to 3.0, such as from 1.2 to 1.7, as described above.

Component (D) is a hydrosilylation catalyst. The hydrosilylation catalyst (D) is added in an amount sufficient to promote the curing reaction of the composition. However, the amount of component (D) may range from 0.01 to 1,000 ppm, alternatively 0.01 to 100 ppm, and alternatively 0.1 to 50 ppm, alternatively 1 to 18 ppm, and alternatively 1 to 7 ppm, of platinum group metal based on weight of the silicone composition.

Suitable hydrosilylation catalysts are known in the art and commercially available. Component (D) may comprise a platinum group metal selected from the group consisting of platinum, rhodium, ruthenium, palladium, osmium or iridium metal or organometallic compound thereof, and a combination thereof. Component (D) is exemplified by platinum black, compounds such as chloroplatinic acid, chloroplatinic acid hexahydrate, a reaction product of chloroplatinic acid and a monohydric alcohol, platinum bis-(ethylacetoacetate), platinum bis-(acetylacetonate), platinum dichloride, and complexes of said compounds with olefins or low molecular weight organopolysiloxanes or platinum compounds microencapsulated in a matrix or core-shell type structure. Complexes of platinum with low molecular weight organopolysiloxanes include 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complexes with platinum. These complexes may be microencapsulated in a resin matrix. Alternatively, the catalyst may comprise 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complex with platinum.

Suitable hydrosilylation catalysts for Component (D) are described in, for example, U.S. Pat. Nos. 3,159,601; 3,220,972; 3,296,291; 3,419,593; 3,516,946; 3,814,730; 3,989,668; 4,784,879; 5,036,117; and 5,175,325 and EP 0 347 895 B. Microencapsulated hydrosilylation catalysts and methods of preparing them are also known in the art, as exemplified in U.S. Pat. No. 4,766,176; and U.S. Pat. No. 5,017,654.

As noted above, the cured polyorganosiloxane according to non-limiting embodiment 1 has a surface having a water contact angle of greater than 90°, such as from greater than 90° to 180°, such as from 100° to 135°, such as from 110° to 130°, as measured by ASTM 5946-04.

Non-Limiting Embodiment 2 of Cured Polyorganosiloxane

In another non-limiting embodiment (Non-limiting Embodiment 2), the cured polyorganosiloxane may be formed by curing a curable composition comprising the following components:

(A′) an organopolysiloxane of the following average structural formula: R.sup.10.sub.kSiO.sub.(4-k)/2

(B′) an organopolysiloxane that contains in one molecule at least two silicon-bonded hydrogen atoms and at least 15 mole % of all silicon-bonded organic groups in the form of aryl groups;

optionally (C′) a branched-chain organopolysiloxane and

(D′) a hydrosilylation catalyst.

Each of components (A′)-(D′), are described in further detail below.

As noted above, component (A′) is represented by the following average structural formula: R.sup.10.sub.kSiO.sub.(4-k)/2

In the above formula, “k” is a number ranging from 0.6 to 2.1 and R.sup.10 designates unsubstituted or halogen-substituted monovalent hydrocarbon groups, which can be exemplified by a methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or a similar alkyl group; a vinyl, allyl, butenyl, pentenyl, hexenyl, or a similar alkenyl group; a phenyl, tolyl, xylyl, naphthyl, or a similar aryl group; a benzyl, phenethyl, or a similar aralkyl group; and 3-chloropropyl, 3,3,3-trifluoropropyl, or a similar halogen-substituted alkyl group. However, in one molecule at least two groups designated by R.sup.1 are alkenyl groups. Most preferable of these alkenyl groups are vinyl groups. Furthermore, in order to reduce damping of light that may be caused by refraction, reflection, scattering, etc., when the light passes through the cured product, it is recommended that in one molecule at least 30 mole %, preferably at least 40 mole % of the groups represented by R.sup.10 be aryl group, in particular, phenyl groups. In the above formula, “a” is a number ranging from 0.6 to 2.1. Component (A′) may have a linear, branched, or a cyclic molecular structure. Molecular structure may be of one type or a combination of two or more types.

Component (A′) may also comprise a linear-chain organopolysiloxane of the following general formula: R.sup.12.sub.3SiO(R.sup.12.sub.2SiO).sub.tSiR.sup.12.sub.3 and/or a branched-chain organopolysiloxane of the following average unit formula: (R.sup.13SiO.sub.3/2).sub.u(R.sup.13.sub.2SiO.sub.2/2).sub.v(R.sup.13.sub.3SiO.sub.1/2).sub.w(SiO.sub.4/2).sub.x(X″″O.sub.1/2).sub.y

In the above formulae, each R.sup.12 and R.sup.13 independently designates unsubstituted or halogen-substituted monovalent hydrocarbon groups, which are the same as defined above. However, in one molecule at least two groups designated by R.sup.12 (for the linear-chain organopolysiloxane) and R.sup.13 (for the branched-chain organopolysiloxane) are alkenyl groups. Most preferable of these alkenyl groups are vinyl groups. In order to reduce damping of light that may be caused by refraction, reflection, scattering, etc., when the light passes through the cured product, it is recommended that in one molecule at least 30 mole %, preferably at least 40 mole % of groups be represented by R.sup.12 (for the linear-chain organopolysiloxane) and R.sup.13 (for the branched-chain organopolysiloxane) be aryl group, in particular, phenyl groups. In the above formula, “t” is a number ranging from 5 to 1,000; “u” is a positive number, “v” is 0 or a positive number, “w” is 0 or a positive number, “x” is 0 or a positive number, “y” is 0 or a positive number; “v/u” is a number ranging from 0 to 10, “w/u” is a number ranging from 0 to 5, “x/(u+v+w+x)” is a number ranging from 0 to 0.3, and “y/(u+v+w+x)” is a number ranging from 0 to 0.4. In addition, X″″ designates a hydrogen atom or an alkyl group. The alkyl groups designated by X″″ may be methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl groups, of which methyl groups are preferable.

Component (B′), which is a cross-linking agent of the curable composition, comprises an organopolysiloxane that contains in one molecule at least two silicon-bonded hydrogen atoms. The silicon-bonded organic groups contained in component (B′) are represented by methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or similar alkyl groups; phenyl, tolyl, xylyl, naphthyl, or similar aryl groups; benzyl, phenethyl, or similar aralkyl groups; and 3-chloropropyl, 3,3,3-trifluoropropyl, or similar halogenated alkyl groups. In order to reduce damping of light that may be caused by refraction, reflection, scattering, etc., when the light passes through the cured product, it is recommended that in one molecule of this component at least 15 mole %, preferably at least 25 mole % of all silicon-bonded organic groups be aryl group. Component (B′) may have a linear, branched, or cyclic molecular structure. Molecular structure may be of one type or a combination of two or more types.

Component (B′) may also comprise a linear-chain organopolysiloxane represented by the following general formula: R.sup.14.sub.3SiO(R.sup.14.sub.2SiO).sub.iiSiR.sup.14.sub.3, and/or a branched-chain organopolysiloxane of the following average unit formula: (R.sup.14SiO.sub.3/2).sub.j(R.sup.14.sub.2SiO.sub.2/2).sub.kk(R.sup.14.sub.3SiO.sub.1/2).sub.ll(SiO.sub.4/2).sub.mm(X″″O.sub.1/2).sub.nn.

In these formulae, R.sup.14 independently designates a hydrogen atoms, or unsubstituted or halogen-substituted monovalent hydrocarbon groups. The monovalent hydrocarbon groups designated by R.sup.14 may be exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, or similar alkyl groups; phenyl, tolyl, xylyl, naphthyl, or similar aryl groups; benzyl, phenethyl, or similar aralkyl groups; and 3-chloropropyl, 3,3,3-trifluoropropyl, or similar halogenated alkyl groups. However, in one molecule, at least two groups designated by R.sup.14 should be formed by hydrogen atoms. Furthermore, in order to reduce damping of light that may be caused by refraction, reflection, scattering, etc., when the light passes through the cured product, it is recommended that in one molecule of this component at least 15 mole %, preferably at least 40 mole % of groups represented by R.sup.3 be aryl group. The preferable aryl groups are phenyl groups. In the formulae, “n” is an integer ranging from 5 to 1,000, “p” is a positive number, “q” is 0 or a positive number, “r” is 0 or a positive number, “s” is 0 or a positive number, “t” is 0 or a positive number, “q/p” ranges from 0 to 10, “r/p” ranged from 0 to 5, “s/(p+q+r+s)” ranges from 0 to 3, and “t/(p+q+r+s)” ranges from 0 to 0.4.

Component (B′) is added in such an amount that the mole ratio of hydrogen atoms contained in this component to alkenyl groups of components (A′) and (C′) is in the range of 0.1 to 5, preferably in the range of 0.5 to 2. If component (B′) is added in an amount less than the recommended lower limit, the obtained composition will not be cured to a sufficient degree. If, on the other hands, the added amount of component (B′) exceeds the recommended upper limit, this will impair heat resistance of a cured product of the composition.

Component (C′) is used for improving adherence of the composition to substrates. This component is a branched-chain organopolysiloxane of the following average unit formula: (R.sup.11SiO.sub.3/2).sub.o(R.sup.11.sub.2SiO.sub.2/2).sub.p(R.sup.11.sub.3SiO.sub.1/2).sub.q(SiO.sub.4/2).sub.r(X″″O.sub.1/2).sub.s In this formula, R.sup.11 independently designates an alkyl group, alkenyl group, aryl group, or an epoxy-containing organic group. As the alkyl group, R.sup.11 may be specifically exemplified by a methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl group, of which methyl group is preferable. As alkenyl group, R.sup.11 may be exemplified by vinyl, allyl, butenyl, pentenyl, or a hexenyl group, of which the vinyl group is preferable. The aryl groups represented by R.sup.11 may be specifically exemplified by phenyl, tolyl, xylyl, and naphthyl groups, of which phenyl groups are preferable. The epoxy-containing organic groups designated by R.sup.11 may be specifically exemplified by 3-glycidoxypropyl, 3,4-epoxycyclohexylethyl, 3,4-epoxybutyl, or 5,6-epoxyhexyl group, of which 3-glycidoxypropyl group is preferable. However, in one molecule, at least 5 mole %, preferably at least 8 mole % of all groups designated by R.sup.11 are alkenyl groups. Furthermore, in one molecule, at least 15 mole %, preferably 25 mole % of all groups designated by R.sup.11 are aryl groups. Moreover, in one molecule, at least 10 mole %, preferably at least 20 mole %, of all groups designated by R.sup.11 are epoxy-containing organic groups. In the above formula, X″″ designates a hydrogen atom or an alkyl group. The alkyl groups designated by X″″ may be methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl groups, of which methyl groups are preferable. In the above formula, “b” is a positive number, “c” is 0 or a positive number, “d” is 0 or a positive number, “e” is 0 or a positive number, and “f” is 0 or a positive number; “c/b” is a number ranging from 0 to 10; “d/b” is a number ranging from 0 to 5; “e/(b+c+d+e)” is a number ranging from 0 to 0.3; and “f/(b+c+d+e)” is a number raging from 0 to 0.02. Component (C′) should have a mass-average molecular weight not lower than 2,000.

Component (C′), when present, is added in an amount of 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and most preferably 0.2 to 10 parts by mass per 100 parts by mass of the sum of components (A′) and (B′). If component (C′) is added in an amount less than the recommended lower limit, this will impair adherence of the obtained cured products to substrates. If, on the other hands, the added amount of component (C′) exceeds the recommended upper limit, this will cause coloring of the cured product.

The description continues in the full USPTO document.